As a result of structure reactivity, isotope effect and pH studies, a single active site side chain, pK equals 8.25, has been implicated in acid base catalysis of hydride transfer in the yeast alcohol dehydrogenase reaction. Solvent isotope effects will be studied in an effort to determine whether hydride transfer and acid-base catalysis occur in a concerted or step-wise fashion. The effect of variations in substrate structure and isotope composition on kinetic parameters for the reaction catalyzed by benzyl alcohol dehydrogenase will be determined. A goal of these studies is a comparison of ground state and transition state interactions between enzyme and substrate for the reactions catalyzed by benzyl alcohol dehydrogenase and yeast alcohol dehydrogenase. A series of isotopically labeled phenylethylamines will be synthesized to be used in a study of the mechanism of action of dopamine beta-hydroxylase.